kn—Alternate  abbreviation  for  knot.  In  meteorology, the more frequently used abbreviation is "kt", but this  should  not  be  confused  with  the  uppercase "KT" meaning kiloton. L LAPSE RATE—The    decrease    of    an    atmospheric variable   with   height:   the   variable   being temperature unless otherwise specified. LCD—Liquid crystal diode. A gray or black display of numbers or shapes commonly used in electronics. LITTORAL —The  coastal  zone  including  the  beach  to the coastal waters. LLWS—Low-level  wind  shear. M M-UNITS—A unit of measurement used in electromagnetic   refractivity   calculations-a modification of N-Units. MEGATON—(MT)     A     multiplication     factor     for nuclear  weapon  yields.  Each  megaton  is  equal  to the   explosive   force   of   1   million   tons   of trinitrotoluene (TNT) explosive. MET—U.S.  Navy  mobile  environmental  team. METEOROLOGY—The  study  of  phenomenon  of  the atmosphere. METVANS —USMC    mobile    meteorological    vans. Highly   transportable,   completely   equipped meteorological  facilities  constructed  as  complete modules in cargo containers. Modules may be used independently or connected to form complete, full- spectrum,   meteorological   support   facilities   in   a forward deployed environment. MHz—Megahertz,  1  million  hertz. MILS—An  angular  measurement  scale  in  which  800 mils equals 45 degrees of arc; a circle is 6400 mils. MMF—U.S.   Marine   Corps   meteorological   mobile facility-weather   personnel   who   operate   USMC Metvans. MRS—Mini rawinsonde system. MSL—Mean  sea  level,  a  suffix  used  after  altitude measurements. MVFR—Marginal  visual  flight  rules. N NATO—North  Atlantic  Treaty  Organization. NAVAID—An  acronym  for  navigation  aid,  usually referring  to  an  aircraft  navigation  aid  such  as  an NDB, VOR, TACAN, VORTAC, or DME. NAVMETOCCOM —Short title for Naval Meteorology   and   Oceanography   Command headquartered   at   the   Stennis   Space   Center, Mississippi. NAVSAR—A   GFMPL   program   used   to   help   plan rescue searches at sea. NBC—An    acronym    for    nuclear,    biological,    or chemical. NOAA—National Oceanic and Atmospheric Administration, a division of the U.S. Department of Commerce. NODDS—Navy oceanographic data distribution system. NOMOGRAM—Any   graphic   product   used   to   find solutions to complex calculations without having to perform the calculations. NOTAM—Notice  to  airmen. NTDS—Navy tactical data system. NUC—An abbreviation for nuclear; used within some NATO messages. NWS—National weather service, a division of NOAA. O OA—Abbreviation  for  shipboard  aviation  operations division,  the  shipboard  division  for  which  most Aerographer’s  Mates  work. OOD—Officer of the deck P PIBAL—An acronym for pilot balloon, a small balloon tracked   with   a   theodolite   to   determine   wind direction and speed. PIREP—Abbreviation  for  pilot  report. Q QFE—A  signal  used  to  indicate  the  value  provided;  the station  pressure. AI-3